Kernel-based linear system identification using augmented Krylov subspaces

Fuente: arXiv
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Autori principali: Matti, Fabio, Andersen, Martin Skovgaard, Chen, Tianshi, Kressner, Daniel
Natura: Preprint
Pubblicazione: 2026
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author Matti, Fabio
Andersen, Martin Skovgaard
Chen, Tianshi
Kressner, Daniel
author_facet Matti, Fabio
Andersen, Martin Skovgaard
Chen, Tianshi
Kressner, Daniel
contents We propose a novel Krylov subspace method for estimating the finite impulse response (FIR) of a one-dimensional linear time-invariant systems. The method approximates the system's FIR using a kernel-based formulation combined with hyperparameter selection based on maximum likelihood estimation (MLE), which requires repeated evaluation of two terms: The data fit $\boldsymbol{y}^{\top} (λ\boldsymbol{I} + \boldsymbol{A})^{-1} \boldsymbol{y}$ and the model complexity $\log(\det (λ\boldsymbol{I} + \boldsymbol{A}))$, where $\boldsymbol{A}$ is a certain positive semidefinite matrix that admits fast matrix--vector products and $λ> 0$ is a regularization parameter. Instead of approximating these two quantities separately, we jointly approximate them using a single augmented Krylov subspace for $\boldsymbol{A}$. One major benefit of augmentation is that we obtain accelerated convergence when approximating the data fit quadratic form, through implicit preconditioning. Thanks to the shift invariance of Krylov subspaces, the extracted approximations can be used to evaluate the MLE objective for many values of $λ$ at little additional cost. We derive error bounds for the approximations, reflecting the benefits of augmentation demonstrated through multiple numerical experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2605_08362
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Kernel-based linear system identification using augmented Krylov subspaces
Matti, Fabio
Andersen, Martin Skovgaard
Chen, Tianshi
Kressner, Daniel
Numerical Analysis
62C10, 65F08, 65F22, 65F40, 93B15, 93B30
We propose a novel Krylov subspace method for estimating the finite impulse response (FIR) of a one-dimensional linear time-invariant systems. The method approximates the system's FIR using a kernel-based formulation combined with hyperparameter selection based on maximum likelihood estimation (MLE), which requires repeated evaluation of two terms: The data fit $\boldsymbol{y}^{\top} (λ\boldsymbol{I} + \boldsymbol{A})^{-1} \boldsymbol{y}$ and the model complexity $\log(\det (λ\boldsymbol{I} + \boldsymbol{A}))$, where $\boldsymbol{A}$ is a certain positive semidefinite matrix that admits fast matrix--vector products and $λ> 0$ is a regularization parameter. Instead of approximating these two quantities separately, we jointly approximate them using a single augmented Krylov subspace for $\boldsymbol{A}$. One major benefit of augmentation is that we obtain accelerated convergence when approximating the data fit quadratic form, through implicit preconditioning. Thanks to the shift invariance of Krylov subspaces, the extracted approximations can be used to evaluate the MLE objective for many values of $λ$ at little additional cost. We derive error bounds for the approximations, reflecting the benefits of augmentation demonstrated through multiple numerical experiments.
title Kernel-based linear system identification using augmented Krylov subspaces
topic Numerical Analysis
62C10, 65F08, 65F22, 65F40, 93B15, 93B30
url https://arxiv.org/abs/2605.08362